The Rio Carnival came alive Saturday with more than two million revelers in outlandish costumes staging a mammoth, samba-driven street festival in the city center. Drawing the huge crowds, a day after legendary King Momo declared the Carnival officially open, was the Cordao da Bola Preta -- one of Rio's oldest and most popular blocos street parties. While the eagerly awaited highlight of the Carnival, the parades of elaborately decorated fantasy floats and scantily dressed women in the Sambadrome, attract mainly the wealthy and foreign tourists, blocos are for all. "Bola Preta is one of the most traditional blocs of the Carioca (Rio) Carnival and everybody participates, particularly blacks (from the favelas)," participant Sandrah Sagrado told AFP. "Bola Preta brings everybody together, people from all districts and neighboring towns," Denise Chagas concurred. Organizers said 2.5 million people took part in the street parade that lasted nearly seven hours. Police put the turnout at 2.3 million. Spurred on by the pulsating samba beat of a marching brass band, Bola Preta fans strutted along Rio Branco Avenue in outlandish costumes, from Cleopatra or Pope to clowns and cross-dressers wearing masks, bright red or fluorescent green wigs and oversized glasses. Under sunny skies and in a good-natured atmosphere, men in baby diapers or wearing garish pink or green tutus danced and sang. Others sported football star Neymar's famous Mohawk hairstyle in multi-colored hues or tried to scare women in their monster disguises. Black polka dots on white is the signature style for Bola Preta (black ball) outfits as, according to city lore, a beautiful, curvy woman in a polka-dot dress was the inspiration for the bloco's name. Igor Moreira, 23, and four friends came bedecked in a Winnie Mouse outfit, complete with polka dot skirts, black stockings and tops. "It's just for fun. This is Carnival, anything goes," he said with a giggle. This year, the Bola Preta street show was wired by the city, allowing it to use four sound trucks, one less than last year. In 2008, as it celebrated its 90th anniversary, Bola Preta was listed as a Rio Cultural Heritage along with its signature song and Carnival classic "Quem Nao Chora Nao Mama" (The squeaky wheel gets the grease). Some 171 street parties were scheduled across the "Marvelous City" this weekend and 400 during the five-day Carnival, which officials hope will attract four million people, including 850,000 tourists. Other Brazilian cities, including Sao Paulo, the country's economic capital, and Salvador de Bahia, the heart of Afro-Brazilian culture, also celebrated the annual pre-Lent festival in style. On Friday Sao Paulo held spectacular parades of allegorical floats paying tribute to Brazil's rich African heritage at its own sambadrome. Meanwhile Brazil's former president Luiz Inacio Lula da Silva, who is recovering from cancer radiation therapy, on Saturday thanked a Sao Paulo samba school for its planned tribute to his life but said he could not be with them. "Gavioes da Fiel," the samba school of the Corinthians, the Sao Paulo soccer team of which Lula is a die-hard fan, said earlier this week it would honor the popular former president with a Carnival parade late Saturday extolling his life of struggle and overcoming the odds. "From the bottom of my heart, I am grateful for your tribute in dedicating your parade this year to my life story," the 66-year-old Lula said in a video message released by his foundation. The popular former president, who was released from a Sao Paulo hospital Friday after completing radiation therapy for his larynx cancer, said he would not be able to attend on the advice of his doctors. But he promised to watch the parade on television and root for his beloved samba school. In Rio, the top 13 competing samba schools were to parade dancers, musicians and elaborately decorated fantasy floats at the renovated Sambadrome Sunday night and Monday night. The contest between the Rio samba schools for the title of Carnival champion is watched with the same fervor as football matches in this soccer-mad nation.